bURNING IN COMPONENTS

acorn · Post by **acorn** » Sat Jan 17, 2015 1:28 pm

Is the practice of burning in components strictly necessary and if so could any one explain why this is needed.

Acorn

Ali Tait · Post by **Ali Tait** » Sat Jan 17, 2015 3:46 pm

Don't see how you can avoid it if you turn whatever it is on..

pre65 · Post by **pre65** » Sat Jan 17, 2015 3:50 pm

I think the real question is - how long.

If you are comparing components, give the new one a good while to settle down, then swap the old one back in.

IslandPink · Post by **IslandPink** » Sat Jan 17, 2015 5:43 pm

Most stuff will run-in of its own accord in a few days when used in an amp.
The exceptions I've found are transformers used at small signal level , like phono step-up transformers, and small interstages or 1:1 isolation transformers / phase-splitters used at line-level or lower signal .
Some of these need burn-in with a larger signal for eg. 2-3 days ( continuous or in chunks ) to open-up the sound . I don't know if it's the cores that need working, or interlayers in the windings which have residual static ( surface charge ) , but the sound can change quite a lot for the better . The worst I've come across were some Lundahl amorphous phase-splitters with kapton interlayers, that were going nowhere after weeks of on/off usage, but they came good after some hammering with a signal 10 to 100x larger with some current behind it .

Mike H · Post by **Mike H** » Mon Jan 19, 2015 1:18 pm

Personally I think it's cobblers

As regards valves, I read somewhere that as soon as you turn 'em on, they start wearing out. So really you should be rationing the number of hours of usage, not 'burning them in'.

Lee S · Post by **Lee S** » Mon Jan 19, 2015 5:03 pm

+1 ^^^

I think it's also a load of rubbish... Maybe mechanical devices like 'speaker drivers, etc, but not electronic components...

jack · Post by **jack** » Mon Jan 19, 2015 5:28 pm

+2

I think that its your ears that burn in - after a while the change wears off and you become more comfortable with what you hear.

I've never seen any deterministic and/or quantitative experimental analysis that can definitively show any "improvements", e.g. in THD or IMD etc., after a "burn in".

The mind is a tricky & complex beast

(flame-proof suit on)

IslandPink · Post by **IslandPink** » Mon Jan 19, 2015 6:04 pm

Christ, those posts are depressing. I seriously wonder why I'm bothering to post on here if people can't hear any burn-in on new capacitors or transformers . I have no idea if it's measurable on THD ( do I care ? ) but it sure as hell is obvious to me when listening and has been since the first circuit I built ( WAD 2A3 ) 13 years ago .

jack · Post by **jack** » Mon Jan 19, 2015 6:16 pm

Hey - why "depressing" - its a personal view - nothing more - consider it my problem if I can't hear any differences - I'm perfectly happy with that, I hope you can be too

Some years ago when I was mostly designing solid state amps I did some recordings of amps when new and a week or so later, then did like-for-like blind testing with some friends (this was probably in the late '80s/early '90s) and our results were inconclusive, i.e. overall, we couldn't differentiate between the original and later recordings. The setup, ISTR, was at the house of a school friend who was a senior producer with Decca Argo, so his kit was VERY good.

The only reason I mentioned THD/IMD etc. is that I'm interested in what goes on - if my ears tell me that there's a change, why is that? I didn't say I couldn't hear a difference, I was merely speculating that if I could, what the cause might be...

Cressy Snr · Post by **Cressy Snr** » Mon Jan 19, 2015 6:19 pm

Well I can certainly hear burn-in. I have heard it on everything I have built.
In fact I have heard burn-in do theopposite of what it usually does. Yes I have heard things get worse over a period of time, despite the fact that voltage measurements and scope probing reveals no change in conditions.
That's a strange one, but it has caused me often to abandon or dismantle something that sonded great, when newly built.

Two amps that have not done this have been the 6B4G monoblocks, which were only dismantled due to me needing more power, and t he present push pull 50W jobbie, that for some reason just seems to get better and better with age.

So, like Mark, I'm a believer. But of course YMMV.

pre65 · Post by **pre65** » Mon Jan 19, 2015 6:22 pm

Cloth ears me.

Never been conscious of capacitor burn it. Not to say they don't though.

Don't take offence Mark, just saying how it is with me.

Neal · Post by **Neal** » Mon Jan 19, 2015 8:18 pm

It's the type of music you listen to Phil!

IslandPink · Post by **IslandPink** » Mon Jan 19, 2015 8:26 pm

That's OK Nick . I guess I'm just a bit shocked. For me the feeling it exists is just clear, I'm aware of it all the time, when changing circuits or doing evaluations ( like on the DHT fil supplies ) . It never seems like a question of debate, or 'belief' , it's just something I allow for and have a good idea of timescales relating to the part involved and the amount of hammer ( current/voltage ) it's going to experience. Certainly it's very subtle if you're talking about resistors or short pieces of wire - I would not be sure ( other than allowing a couple of hours playing ) if there was anything going on there ; but for caps and transformers ....

For example if you had a good 300B ( eg . my KR300B's

) and put a new cathode-bypass cap on one , it would sound like the worst cheap Chinese 300B for about 1 or 2 hours, then by 5 hours it'd be quite close to normal, then by 10 or 20 hours, almost indistinguishable from before .

jack · Post by **jack** » Tue Jan 20, 2015 10:59 am

Oh, I'm aware of changes alright, it's just that I'm pretty certain its mostly in my mind. The problem for me is that I normally can't do an A/B blind test with what it sounded like prior to the change - I did that years ago as I mentioned and, personally, feel much of this is an honest artefact of our hearing.

We'll just have to agree to differ, I guess

chris661 · Post by **chris661** » Tue Jan 20, 2015 12:10 pm

I can see that mechanical devices need break-in time. Tiny cracks in the epoxy-soaked spider, stuff like that.

Electrical devices, though?
I'm not so sure. Electrolytic capacitors, maaaaybe. If the liquid electrolyte has settled somehow (which I sincerely doubt), then I'd expect shaking them around a bit to even things out.

Mark, would it be possible to organise some kind of test for the next Owston?
I'm thinking a pair of input transformers on a phono stage or similar, and swap out old vs new. It'd have to be a blind test, though, or people might walk in with preconceptions.
Either way, something that's easily switchable (via banana plugs or similar) would quickly give an indicator.

Chris

audio-talk

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